In recent years, NAND type flash memories having a two-dimensional structure are confronting the limit of scaling. Under the circumstances, there have increased the demands for techniques about three-dimensional structure memories that can realize a larger memory capacity by use of integration based on stacking of layers without depending on scaling. As a three-dimensional structure memory, for example, there has been proposed a NAND type flash memory having a three-dimensional structure in which NAND strings are vertically arranged.
According to three-dimensional structure memories, as the memory capacity is set larger, the number of stacked layers is increased, and the product development becomes more difficult together with this. For example, when memory patterns are formed by use of lithography, the overlay accuracy between upper and lower layers is important. As the number of stacked layers is increased, it becomes more difficult to detect a “mark” for alignment measurement present on a lower layer. The alignment measurement using a mark is categorized into bright field measurement and diffraction light measurement. The bright field measurement is a measuring method of performing evaluation based on a contrast of light intensity obtained by forming an image with reflected light from a mark. The diffraction light measurement is a measuring method of performing evaluation based on a change in diffraction light intensity obtained by scanning a mark with laser light. In order to attain a high contrast or a high degree of diffraction light intensity, the measurement conditions, mark design, and/or film structure need to be optimized. However, a changeover of the mark design or film structure entails a process alteration and so has a significant impact.